a simple json file migration for the drupal 7 (maybe 6?) migrate module

1.json

{
      "title": "this is a title",
      "content": "this is a body",
      "date": "2009-01-01",
      "url":"http://oldsite.com/123/test",
      "image": "test.jpg",
      "id": 1
}

json.migration.php

<?php

class JSONMigration extends Migration {
  /**
   * A constructor 
   */
  public function __construct() {
    parent::__construct(MigrateGroup::getInstance('json_migration'));
    // list of the file ids [1,2,3,4,5,6]
    $list_url = 'http://localhost/json/list.json';
    //pattern where the files are at
    $item_url = 'http://localhost/json/:id.json';
    //no options, or you could specify some
    $http_options = array();
    //map for the migration
    $this->map = new MigrateSQLMap($this->machineName,
        array(
          'muid' => array(
            'type' => 'int',
            'not null' => true,
          ),
        ),
        MigrateDestinationNode::getKeySchema()
    );
    $this->source = new MigrateSourceList(
        new MigrateListJSON($list_url),
        new MigrateItemJSON($item_url, $http_options),
        $this->fields()
    );
    //destination node type is json (because this is an example)
    $this->destination = new MigrateDestinationNode('json');
    //map node's title field to the title in the json content
    $this->addFieldMapping('title', 'title');
    //map node's body field to the content in the json content
    $this->addFieldMapping('body', 'content');
    //map node's field_id field to the id in the json content
    $this->addFieldMapping('field_id', 'id');
    //map node's field_name field to the title in the json content
    $this->addFieldMapping('field_name', 'title');
    //map node's created field to the date in the json content
    $this->addFieldMapping('created', 'date');
    //apparently you can do stuff like this:
    $this->addFieldMapping('comment', null)->defaultValue(COMMENT_NODE_CLOSED);
  }
  
  /**
   * Return the fields (this is cleaner than passing in the array in the MigrateSourceList class above)
   * @return array
   */
  function fields() {
    return array(
      'title' => 'The title of the content',
      'content' => 'The body of the content',
      'date' => 'Date associated with the content',
      'url' => 'Source url associated with the content',
      'image' => 'Image Source url associated with the content',
      'id' => 'Source ID associated with the content',
    );
  }
  
  /**
   * Remap fields as needed
   * @param type $row 
   */
  function prepareRow($row) {
    //rewrite the date as a timestamp
    list($year, $month, $day) = explode('-', $row->date);
    $row->date = mktime(0, 0, 0, $month, $day, $year);
  }
  
}

json_migration.info

name = "JSON MIGRATION"
description = "Module to migrate content from old site to Drupal 7 (json format)"
package = "Development"
core = 7.x
dependencies[] = migrate
dependencies[] = field
dependencies[] = file
dependencies[] = image
dependencies[] = number
dependencies[] = text

files[] = json_migration.module
files[] = json.migration.php

json_migration.module

<?php

/**
 * You must implement hook_migrate_api(), setting the API level to 2, for
 * your migration classes to be recognized by the Migrate module.
 */
function json_migration_migrate_api() {
  $api = array(
    'api' => 2,
  );
  return $api;
}

list.json

[1,2,3,4,5]